Six cotton varieties were evaluated for susceptibility to infestation with
certain piercing sucking insects, cotton leafworm and the pink and spiny bollworms at
the Experimental Farm, Sakha Agricultural Research Station (North Delta) during
2002 and 2003 seasons. The highest n umbers a f aphids e xlsted on cotton variety
Giza 85, white Giza 89 and Giza 70 harboured the least numbers. However, Giza 45
and Giza B9 were the least infested varieties with whiteflies and jassids which showed
the highest affinity to varieties Giza 89 and Giza 86, respectively. On the other hand, Giza 88 attained the highest number of cotton leafworm
larvae. while Giza 89 exhibited the lowest number of this insect. Also, Giza 45 (late
bloomer variety) was the most susceptible to infestation with Pectinophora
gossyp < /em>ie/la (Saund.) and Eanas insulana (Boisd.) and harboured the highest
numbers of larvae 0 f t he two bollworms. However, Giza 89 (early bloomer variety)
was the most resistant one to both bollworms. The combined effect of temperature, relative humidity and wind velocity was
more pronounced on piercing sucking insect populations on Giza 45 and Giza 85
varieties in the second season, with values of 71.50 and 70%. respectively.